Thresholding is one of the classical methods for image segmentation, which has the advantages of simple calculation, high efficiency and fast speed [1]}.
The selection of the threshold is the core algorithm of threshold segmentation [2]}.
There are two main methods, the first one is iterative thresholding method, which can obtain the good results
for the images with high global contrast [3]}.
Another one is the maximum inter class variance based on Otsu method, which can obtain the satisfactory
result for most images [4]}. This method is considered to be the best method for automatic threshold selection because it is easy to calculate and is not affected by the change of image contrast and brightness [5]}.
